WCF::handleException() Unhandled exception: Class 'wcf\system\template\TemplateEngine' not found

#0 /usr/www/users/martingr/rauchfrei-forum.net/wcf/lib/system/WCF.class.php(145): wcf\system\WCF->initTPL()
#1 /usr/www/users/martingr/rauchfrei-forum.net/wcf/global.php(25): wcf\system\WCF->__construct()
#2 /usr/www/users/martingr/rauchfrei-forum.net/global.php(13): require_once('/usr/www/users/...')
#3 /usr/www/users/martingr/rauchfrei-forum.net/index.php(12): require_once('/usr/www/users/...')
#4 {main}